Particle size results

Poorly sorted sediments comprise very different particle sizes, resulting in a dense rock fabric wifh low porosify. As a resulf the connate water saturation is high, leaving little space for the storage of hydrocarbons. Conversely, a very well sorted sediment will have a large volume of space between the evenly sized components, a lower connate water saturation and hence a larger capacity to store hydrocarbons. Connate water is the water which remains in the pore space after the entry of hydrocarbons. 

In fluidized-bed adsorbers, the combination of high gas rate and small adsorbent particle size results in suspension of the adsorbent, giving it many of the characteristics of a fluid. Fluidized bed adsorbers, therefore, lend themselves to truly continuous, countercurrent, multistage operation. Adsorbent inventory is minimized. 

The influence of physicochemical factors is closely related to surface phenomena at the solid-liquid boundary. It is especially manifested by the presence of small particles in the suspension. Large particle sizes result in an increase in the relative influence of hydrodynamic factors, while smaller sizes contribute to a more dramatic influence from physicochemical factors. No reliable methods exist to predict when the influence of physicochemical factors may be neglected. However, as a general rule, for rough evaluations their influence may be assumed to be most pronounced in the particle size range of 15-20 tm. 

Modern high-performance liquid chromatography has been developed to a very high level of performance by the introduction of selective stationary phases of small particle sizes, resulting in efficient columns with large plate numbers per litre. 

Moreover, particle size can significantly affect the material properties of the nanoparticles and is important for their interaction with the biological enviromnent (e.g., as concerns their ability to pass fine capillaries or to leave the vascular compartment via fenestrations after intravenous administration). Particle sizing results are thus crucial parameters in the development and optimization of preparation processes as well as in the evaluation of dispersion stability. Particle sizing, however, has also been employed for other purposes for example, to evaluate the size dependence of the nanoparticle matrix properties [1] or to obtain additional information on the particle shape [2,3]. 

In the third country, roller compaction was substituted for the slugging process. While the sizing of the slugs and compacts were completed on different machines, and the particle size results were not exactly the same in each situation, the tablet content uniformity results were equivalent. Content uniformity relative standard deviations of 1.5-2.0% ( = 10 tablets) were routinely achieved. The tablet dissolution profiles averaged 95% or higher within 30 minutes in each country. 

The role of particle size of the atomized droplets in determining flavor retention is also controversial. Several workers have reported that larger particle sizes result in improved flavor retentions (2, 9, 23, 24, 43). To the contrary,... 

An example of the second approach is penicillin G procaine suspensions, where an increase in the particle size resulted in prolongation of the therapeutic level (0.03 unit/mL) from 24 hours for particles at 1 to 2 am to more than 72 hours for particles at 150 to 250 pm.23... 

Differences in geometry and polarity of the dye molecules can lead to wide variations in these finishing or dye-specific properties and can have a marked effect on the absorption characteristics of all dyes, irrespective of whether singlecomponent or combination dyeing processes are used. For instance, uneven dyeing may occur when an unequal distribution of particle size results in insufficient dispersion stability and hence crystal growth and precipitation at the substrate surface. 

The particle size of the packing material determines the number of theoretical plates per unit length that can be generated (see Section 1.3.4). Small particle sizes result in high efficiencies however, increased backpressure can occur as a result of the decreased column permeability. If the small particles are packed into shorter columns the speed of analysis will increase at the same efficiency. 

Tapioca starch and chemically modified tapioca starches are easily converted to instant (pregelatinized) forms (also known as cold-water-soluble starch). This physical modification is brought about by pasting of the starch and subsequent drying as described in Section 12.4. Control of particle size is critical to texture and rehydration rate when the product is redispersed in water.68 Fine particle size results in a smooth texture on redispersion, e.g. in pudding preparation.69 As a comparison, coarse texture could be more desirable in fruit- or vegetable-based foods. 

In Table 3, the observed orders in CP and D2 are given. For both the LTL [0.47] and Si02 support, an increase in particle size results in a significant increase of the positive order in CP and a more negative order in D2. 

Data Transformation. The raw size distribution obtained in PCS is intensity weighted. Most particle sizing results are either mass, area, or number weighted. Therefore, to compare results, the PCS measurements would have to be transformed. If the ratio of the concentrations in each peak is desired, then a transformation is also necessary. The intensity of light scattered by a sphere is given by... 

Liquid-solid mass transfer is typically not limiting due to the small particle size resulting in large particle surface area/volume of reactor, unless the concentration of the particles is very low, and or larger particles are used. In the latter case, intraparticle mass-transfer limitations would also occur. Ramachandran and Chaudhari (Three-Phase Catalytic Reactors, Gordon and Breach, 1983) present several correlations for liquid-solid mass transfer, typically as a Sherwood number versus particle Reynolds and Schmidt numbers, e.g., the correlation of Levins and Glastonbury [Trans. Inst. Chem. Engrs. 50 132 (1972)] ... 

The endotherm that peaked at 651°C intensifies steadily with decreasing particle size, as is the case for the associated DTG peak. This endotherm represents increased formation of liquid phase with decreasing particle size. The enhanced weight loss, indicated by the DTG traces with decreasing particle size, does not coincide with the formation of detectable new crystalline phases in the coarse particle sizes, but does correspond to XRD detection of the formation of sodium disilicate in the fine particle size. Thus, decreasing particle size results in a significantly enhanced low temperature liquid phase attack on silica grains. 

A reduction in particle size results in an increase in the surface area, which facilitates an increase in the dissolution rate and therefore, also, an increase in the rate of absorption. Drugs administered as suspension are generally rapidly absorbed because of the large available surface area of the dispersed solid. For solid dosage forms such as tablets and capsules, decreasing the particle size facilitates dissolution and thus absorption. Figure 6.8 shows the effect of particle size on absorption and resultant blood levels after oral administration of chloramphenicol in rabbits. Peak blood levels occurred much faster with the smaller... 

Selection of an appropriate delay time range and a scheme for spacing them among correlator channels is necessary to ensure that intensity contributions are sampled from all of the particles in the sample [49,85]. Shaumeyer et al. [62] have explored the effect of the selected value of last delay time on particle size results based on the method of cumulants and single exponential methods. Stepanek [49] discusses the effect of incomplete data sets on Laplace inversion techniques. 

Horticultural Vermiculite —Grade of vermiculite sold for horticultural applications. Such grades of vermiculite have smaller particle size resulting in improved water retention, particle strength, and wettability than coarser grades of vermiculite. 

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